<html>
<head>
<style>
html::first-letter { float: right; }
html::before { content:"before text"; float:right; }
span::before { content:"before text"; float:right; }
</style>
</head>
<body>
<span>
  <div></div>
</span>
<button onclick="document.body.style.width='100px'">Click</button>
</body>
</html>
